I am growing Heliopsis Lorraine Sunshine from seed this year, and it really has some striking variegation! Not all of the seedlings were variegated - about half, I think. Bluestone sells it:

Here is a link that might be useful: Heliopsis Lorraine Sunshine at Bluestone

Bouquets for your house or are you selling them? Some foliage that would do OK for yourself would not hold up for commercial sales is why I'm asking.

There are multiple euonymous BTW, some with yellow, some with white variegation.

Variegated boxwood is available too. Holds up extremely well, very common here at every florist.

Not variegated but there are eucalyptus that are hardy or could be brought in for winter and their silver foliage works so well in bouquets.

Hosta and canna leaves make lovely fillers for bouquets. The variegated cannas like Tropicana or Bengal Tiger are beautiful rolled around flowers. I like to use sprigs of either purple or golden berberis too. Just be careful of the thorns.

phylrae, i agree w/ all the above posters; excellent suggestions. we grow soooo many bold variegation woodies here>>> take a look at our website photos and if something strikes you, i can give you the i.d. if you just say something like "the Shrubs pg., photo 4". eventually all the photos will have captions- but not yet!!
best,
mindy
www.cottonarboretum.com/
a teaching website

off the top of my head, for small shrubs, i would recommend:
deutzia chardonnay pearls (bright yell foliage)
mini. varieg. weigela (not monet- weak plant)
various variegated deutzia
diervilla cool splash
sambucus madonna
var.philadelphus
cotinus
** don't forget, 'large' shrubs don't have to be large; you can keep them pruned smaller, incl sambucus, 9 bark etc.Even some trees can be coppiced so that they are shrub size, i.e. robinia freesia(sp); catalpa aurea, acer negundo (there are bold gn/wh and gn/yell varieg. varieties)etc.

perenn:
new yellow and gn varieg phlox
persicaria lance corporal and red dragon
falopia variagata
liysimachia golden alexander and atropurpurea
hakonechloa aureo marg.
ass.colocasias like black beauty
filipendula varieg and aurea
ligularia britt marie crawford

Here is a link that might be useful: The Cotton-Arbo retum

Wow, those are all great suggestions! I sell individual mixed bouquets(roses, lilies, and other bulbs & perennial flowers)locally. The Cotton-Arbo retum info/pics were great too. Thank you! :0)Phyl

Variegated Iris and Variegated tulips have really nice straight foliage or even some really tall regular irises( I have some tall reblooming irises and the tall leaves have a limey green, green and blue stripe look to them.) but I don't know how they hold up in a vase.

Variegated Solomen's Seal has very very pretty foliage.

http://www.flower-garden-bulbs.com/images/storing-flower-bulbs.jpg

Here is a link that might be useful: {{gwi:243613}}

The variegated boxwood would be borderline for you if you are in a colder area of zone 5. Mine basically dies down to where the snow line was when it got the coldest. I'm not sure that it will ever get big enough to use for cutting the foliage (mine is probably about 6 years old and about 18" high,) but you may have a microclimate where it will get bigger.

I don't generally cut for bouquets, so you would have to try plants out to see what does well in a vase, but some plants with interesting foliage in my garden or others I've seen include:
variegated dogwoods, kousa, shrubby and pagoda
hosta, which I've seen used beautifully in a bouquet
sambucus/elderberry, Sutherland gold, black beauty, black lace
Japanese maples
Painted ferns
perennial geraniums such as 'Midnight Reiter' (dark purple), phaeum 'Margaret Wilson' (yellow & green streaks)
Maybe some of the variegated grasses?